Variable displacement swash-plate compressor

ABSTRACT

A compressor includes an actuator that is configured to change the inclination angle of a swash plate. A movable body, which is part of the actuator, has a primary acting portion and a secondary acting portion. The swash plate has a primary receiving portion and a secondary receiving portion. When the inclination angle of the swash plate is maximized, the primary acting portion contacts the primary receiving portion to push the swash plate. When the inclination angle of the swash plate is minimized, the secondary acting portion contacts the secondary receiving portion to push the swash plate.

BACKGROUND OF THE INVENTION

The present invention relates to a variable displacement swash-plate compressor.

Japanese Laid-Open Patent Publication No. 52-131204 discloses a variable displacement swash-plate compressor (hereinafter referred to as a compressor). This type of compressor includes a housing, a drive shaft, a swash plate, a link mechanism, single-headed pistons, a link mechanism, and a control mechanism.

The housing has a swash plate chamber, cylinder bores, and a discharge chamber. The drive shaft is rotationally supported by the housing. The swash plate is accommodated in the swash plate chamber to be rotational with the drive shaft. The link mechanism is located between the drive shaft and the swash plate. The link mechanism allows the inclination angle of the swash plate to be changed. The inclination angle is the angle of the swash plate in relation to a direction perpendicular to the axis of the drive shaft. The pistons are reciprocally accommodated in the cylinder bores. The conversion mechanism uses rotation of the swash plate to reciprocate the pistons in the cylinder bores by a stroke corresponding to the inclination angle. The inclination angle of the swash plate is changed by an actuator. The actuator is controlled by the control mechanism.

More specifically, the link mechanism includes a lug member, a hinge ball, and a link. The lug member is located in the swash plate chamber and is fixed to the drive shaft. The hinge ball is fitted about the drive shaft to be arranged between the swash plate and the drive shaft. The hinge ball includes a spherical portion, which slidably contacts the swash plate, and a receiving portion, which is located in the vicinity of the actuator. The receiving portion is an annular and flat surface arranged to be coaxial with the drive shaft. The link is provided between the lug member and the swash plate. The swash plate is pivotally connected to the lug member via the link.

The actuator includes the lug member, a movable body, and a control pressure chamber. The movable body has a cylindrical shape that is coaxial with and is fitted about the drive shaft. The movable body has an acting portion at a position in the vicinity of the hinge ball. The acting portion is an annular and flat surface coaxial with the drive shaft. The acting portion and the receiving portion contact each other in an area about the drive shaft. The movable body is thus engaged with the swash plate via the hinge ball. The control pressure chamber is defined by the lug member and the movable body. The pressure in the control pressure chamber moves the movable body along the axis of the drive shaft. The control mechanism uses a pressure regulation valve to regulate connection between the discharge chamber and the control pressure chamber, thereby increasing or decreasing the pressure in the control pressure chamber.

In this type of compressor, when the control mechanism controls and increases the pressure in the control pressure chamber, the movable body is moved along the axis so that the acting portion pushes the receiving portion along the axis. This moves the hinge ball along the axis so that the swash plate slides on the hinge ball in a direction for reducing the inclination angle. In contrast, when the control mechanism controls and decreases the pressure in the control pressure chamber, the movable body and the hinge ball are moved in a direction opposite to the above mentioned direction, so that the swash plate slides on the hinge ball in a direction for increasing the inclination angle. In this manner, by moving the movable body along the axis, the inclination angle of the swash plate is changed and the displacement per rotation of the drive shaft is increased or decreased.

In this type of compressor, the swash plate has a top dead center associated part for positioning each piston at the top dead center and a bottom dead center associated part for positioning each piston at the bottom dead center. The inclination angle of the swash plate is changed by pivoting the swash plate about the top dead center associated part without changing the top clearance of the pistons. The position at which the acting portion and the receiving portion contact each other has a structure described below. For example, the acting portion and the receiving portion contact each other in an area about the drive shaft as described above. In another structure, the acting portion and the receiving portion contact each other at a position that is closer to the top dead center associated part than the drive shaft in a direction perpendicular to the axis of the drive shaft. In this case, however, the contact position at which the acting portion and the receiving portion contact each other is close to the center of moment of the load acting on the swash plate. The contact position is also close to the top dead center associated part, at which the compression reaction force applied to the swash plate, for example, by the pistons is great. As a result, the load acting on the movable body is increased when the inclination angle is decreased. In this case, the inclination angle cannot be quickly changed in response to changes in the driving state, for example, of the vehicle, and high controllability cannot be achieved.

Thus, to increase the thrust of the movable body to act against such load, the pressure receiving area of the movable body may be increased. However, an increased pressure receiving area of the movable body increases the diameter of the actuator, which prevents the entire device from being reduced in size.

The contact position of the acting portion and the receiving portion may be changed to a position between the drive shaft and the bottom dead center associated part in the direction perpendicular to the axis of the drive shaft. In this case, the contact position is distant from the center of moment of the load acting on the swash plate, and the movable body receives little influence from the compression reaction force. As a result, the load acting on the movable body is decreased when the inclination angle is decreased. Thus, the inclination angle can be quickly changed in response to changes in the driving state, for example, of a vehicle, and high controllability is achieved. This, however, increases the stroke of the movable body when the inclination angle is changed. As a result, the axial dimension of the actuator is increased, hindering the entire device from being reduced in size.

SUMMARY OF THE INVENTION

An objective of the present invention is to provide a variable displacement swash-plate compressor that achieves high controllability and is reduced in size.

In accordance with one aspect of the present invention, and in accordance with one aspect of the present invention, a variable displacement swash-plate compressor is provided that includes a housing, in which a swash plate chamber and a cylinder bore are defined, a drive shaft rotationally supported by the housing, a swash plate rotational in the swash plate chamber by rotation of the drive shaft, a link mechanism, a piston, a conversion mechanism, an actuator, and a control mechanism. The link mechanism is arranged between the drive shaft and the swash plate. The link mechanism allows change of an inclination angle of the swash plate with respect to a direction perpendicular to an axis of the drive shaft. The piston is reciprocally received in the cylinder bore. The conversion mechanism causes the piston to reciprocate in the cylinder bore by a stroke corresponding to the inclination angle of the swash plate through rotation of the swash plate. The actuator is configured to change the inclination angle of the swash plate. The control mechanism controls the actuator. The link mechanism includes a lug member, which is located in the swash plate chamber and is fixed to the drive shaft, and a transmitting member, which transmits rotation of the lug member to the swash plate. The actuator includes the lug member, a movable body, and a control pressure chamber. The movable body is rotational integrally with the swash plate. The movable body is configured to change the inclination angle of the swash plate by moving along the axis of the drive shaft. The control pressure chamber is defined by the lug member and the movable body. The movable body is moved by changing a pressure in the control pressure chamber. The movable body has a primary acting portion and a secondary acting portion, which are configured to push the swash plate with the pressure in the control pressure chamber. The swash plate has a primary receiving portion and a secondary receiving portion, which are pushed by the primary acting portion and the secondary acting portion. A top dead center associated part for positioning the piston at a top dead center and a bottom dead center associated part for positioning the piston at the bottom dead center are defined on the swash plate. The primary acting portion is configured to contact the primary receiving portion to push the swash plate when the inclination angle of the swash plate is maximized. The secondary acting portion is configured to contact the secondary receiving portion to push the swash plate when the inclination angle of the swash plate is minimized. The secondary acting portion is located between the primary acting portion and the bottom dead center associated part.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a compressor according to one embodiment, illustrating a state of the maximum displacement;

FIG. 2 is a block diagram showing the control mechanism of the compressor;

FIG. 3 is a front view of the swash plate of the compressor;

FIG. 4 is a rear view of the lug plate of the compressor;

FIG. 5 is a cross sectional side view showing the lug plate and the movable body assembled to the drive shaft of the compressor;

FIG. 6 is a cross sectional side view showing the movable body assembled to the drive shaft;

FIG. 7 is a rear view of the movable body;

FIG. 8 is an enlarged partial cross-sectional view showing the area including the movable body and the swash plate when the displacement is maximized;

FIG. 9 is an enlarged partial cross-sectional view showing the area including the movable body and the swash plate in a first inclination range;

FIG. 10 is an enlarged partial cross-sectional view showing the area including the movable body and the swash plate at the boundary between the first inclination range and a second inclination range;

FIG. 11 is an enlarged partial cross-sectional view showing the area including the movable body and the swash plate in the second inclination range;

FIG. 12 is an enlarged partial cross-sectional view showing the area including the movable body and the swash plate when the displacement is minimized;

FIG. 13 is an enlarged partial cross-sectional view showing the area including the movable body and the swash plate when displacement is maximized in a compressor of a comparison example; and

FIG. 14 is an enlarged partial cross-sectional view showing the area including the movable body and the swash plate when displacement is minimized in the compressor of the comparison example.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

One embodiment of the present invention will now be described with reference to the drawings. The compressor of the embodiment is a variable displacement swash-plate compressor with single-headed pistons. This compressor is installed in a vehicle and each included in the refrigeration circuit in the air conditioner of the vehicle.

As shown in FIG. 1, the compressor includes a housing 1, a drive shaft 3, a swash plate 5, a link mechanism 7, pistons 9, pairs of shoes 11 a, 11 b, an actuator 13, and a control mechanism 15, which is illustrated in FIG. 2.

As shown in FIG. 1, the housing 1 has a first housing member 17, a second housing member 19, a cylinder block 21, and a valve assembly plate 23. In the present embodiment, the front-rear direction is defined as shown in FIG. 1.

The first housing member 17 has a front wall 17 a, which extends radially, and a circumferential wall 17 b, which is integrated with the front wall 17 a and extends rearward. A part of the first housing member 17 that is constituted by the front wall 17 a and the circumferential wall 17 b has a cylindrical shape with a closed end. The front wall 17 a and the circumferential wall 17 b define a swash plate chamber 25 in the first housing member 17.

The front wall 17 a has a boss 17 c, which projects forward. The boss 17 c accommodates a shaft sealing device 27. The boss 17 c has a first shaft hole 17 d, which extends in the front-rear direction. The first shaft hole 17 d accommodates a first plain bearing 29 a.

The circumferential wall 17 b has an inlet 250, which communicates with the swash plate chamber 25. An evaporator 103 is connected to the inlet 250 via a pipe 203. This allows low-pressure refrigerant gas delivered by the evaporator 103 to flow into the swash plate chamber 25 via the inlet 250. Thus, the pressure in the swash plate chamber 25 is lower than that in a discharge chamber 35, which will be discussed below.

A part of the control mechanism 15 is arranged in the second housing member 19. The second housing member 19 has a first pressure regulation section 31 a, a suction chamber 33, the discharge chamber 35, a discharge passage 36, and an outlet 360. The first pressure regulation section 31 a is located in the central part of the second housing member 19. The discharge chamber 35 has an annular shape and is located in a radially outer part of the rear housing member 19. The suction chamber 33 has an annular shape and is located between the first pressure regulation section 31 a and the discharge chamber 35 in the second housing member 19.

The discharge chamber 35 communicates with the outlet 360 via the discharge passage 36. A condenser 101 is connected to the outlet 360 via a pipe 201. A check valve 38 is provided in the discharge passage 36. The check valve 38 is switchable between an open state and a closed state. Specifically, the check valve 38 is switched to the open state when the differential pressure of the discharge chamber 35 relative to the condenser 101 is greater than or equal to a predetermined value. In contrast, the check valve 38 is switched to the closed state when the differential pressure of the discharge chamber 35 relative to the condenser 101 is less than the predetermined value. When the check valve 38 is switched to the open state, the refrigerant gas in the discharge chamber 35 flows to the condenser 101 via the discharge passage 36, the outlet 360, and the pipe 201. When the check valve 38 is switched to the closed state, refrigerant gas is prevented from flowing back from the condenser 101 to the discharge chamber 35.

The cylinder block 21 includes cylinder bores 21 a, the number of which is the same as that of the pistons 9. The cylinder bores 21 a are arranged at equal angular intervals in the circumferential direction. The front end of the each cylinder bore 21 a communicates with the swash plate chamber 25. The cylinder block 21 also has retainer grooves 21 b, which limit the maximum opening degree of suction reed valves 41 a, which will be discussed below.

The cylinder block 21 further has a second shaft hole 21 c, which communicates with the swash plate chamber 25 and extends in the front-rear direction of the compressor. The second shaft hole 21 c accommodates a second plain bearing 29 b. The first plain bearing 29 a and the second plain bearing 29 b may be replaced by rolling-element bearings.

The cylinder block 21 further has a spring chamber 21 d. The spring chamber 21 d is located between the swash plate chamber 25 and the second shaft hole 21 c. The spring chamber 21 d accommodates a restoration spring 37. The restoration spring 37 urges the swash plate 5 forward when the inclination angle of the swash plate 5 is minimized. The cylinder block 21 also includes a suction passage 39, which communicates with the swash plate chamber 25.

The valve assembly plate 23 is located between the second housing member 19 and the cylinder block 21. The valve assembly plate 23 includes a valve base plate 40, a suction valve plate 41, a discharge valve plate 43, and a retainer plate 45.

The valve base plate 40, the discharge valve plate 43, and the retainer plate 45 include suction ports 40 a, the number of which is equal to that of the cylinder bores 21 a. The valve base plate 40 and the suction valve plate 41 include discharge ports 40 b, the number of which is equal to that of the cylinder bores 21 a. The cylinder bores 21 a communicate with the suction chamber 33 through the suction ports 40 a and communicate with the discharge chamber 35 through the discharge ports 40 b. Furthermore, the valve base plate 40, the suction valve plate 41, the discharge valve plate 43, and the retainer plate 45 include a first communication hole 40 c and a second communication hole 40 d. The first communication hole 40 c connects the suction chamber 33 to the suction passage 39. This connects the swash plate chamber 25 to the suction chamber 33.

The suction valve plate 41 is provided on the front surface of the valve base plate 40. The suction valve plate 41 includes suction reed valves 41 a, which are allowed to selectively open and close the suction ports 40 a by elastic deformation. The discharge valve plate 43 is located on the rear surface of the valve base plate 40. The discharge valve plate 43 includes discharge reed valves 43 a, which are allowed to selectively open and close the discharge ports 40 b by elastic deformation. The retainer plate 45 is provided on the rear surface of the discharge valve plate 43. The retainer plate 45 limits the maximum opening degree of the discharge reed valves 43 a.

The drive shaft 3 has a cylindrical outer circumferential surface 30. The drive shaft 3 is inserted in the boss 17 c toward the rear of the housing 1. The front end of the drive shaft 3 is supported by the shaft sealing device 27 in the boss 17 c and is supported by the first plain bearing 29 a in the first shaft hole 17 d. The rear end of the drive shaft 3 is supported by the second plain bearing 29 b in the second shaft hole 21 c. In this manner, the drive shaft 3 is supported by the housing 1 to be rotational about the axis O. A second pressure regulation section 31 b is defined in the second shaft hole 21 c in a part rearward of the rear end of the drive shaft 3. The second pressure regulation section 31 b communicates with the first pressure regulation section 31 a through the second communication hole 40 d. The first and second pressure regulation sections 31 a, 31 b constitute a pressure regulation chamber 31.

O-rings 49 a, 49 b are provided on the rear end of the drive shaft 3. The O-rings 49 a, 49 b are located between the drive shaft 3 and the circumferential wall of the second shaft hole 21 c to seal off the swash plate chamber 25 and the pressure regulation chamber 31 from each other.

The link mechanism 7, the swash plate 5, and the actuator 13 are mounted to the drive shaft 3. The link mechanism 7 includes first and second swash plate arms 5 e, 5 f provided on the swash plate 5 shown in FIG. 3, a lug plate 51 shown in FIG. 4, and first and second lug arms 53 a, 53 b provided on the lug plate 51. The first and second swash plate arms 5 e, 5 f correspond to transmitting members of the present invention. The lug plate 51 corresponds to a lug member of the present invention. For illustrative purposes, part of the first swash plate arm 5 e is omitted by using a break line in FIG. 1. The same applies to FIGS. 8 to 14, which will be discussed below.

As shown in FIG. 3, the swash plate 5 has a swash plate main portion 50, a weight 5 c, and the first and second swash plate arms 5 e, 5 f. The swash plate main portion 50 has an annular flat-plate like shape. As shown in FIG. 1, the swash plate main portion 50 has a front surface 5 a, which faces forward in the swash plate chamber 25, and a rear surface 5 b, which faces rearward in the swash plate chamber 25. As shown in FIG. 3, a top dead center associated part T for positioning each piston 9 at the top dead center and a bottom dead center associated part U for positioning each piston 9 at the bottom dead center are defined on the swash plate main portion 50. Also, a bottom dead center plane D is defined in the swash plate main portion 50. The bottom dead center plane D includes the top dead center associated part T, the bottom dead center associated part U, and the drive shaft axis O. Further, a first direction A1 is defined in the swash plate main portion 50 as indicated by the solid arrow. The first direction A1 is perpendicular to the axis O of the drive shaft 3 and is directed from the top dead center associated part T toward the bottom dead center associated part U.

As viewed in FIG. 3, the right side of the bottom dead center plane D is defined as a first side, and the left side of the bottom dead center plane D is defined as a second side.

The swash plate main portion 50 includes a through-hole 5 d. The drive shaft 3 is inserted in the through-hole 5 d. Two flat guide surfaces 52 a, 52 b are provided in the through-hole 5 d. The guide surfaces 52 a, 52 b contact the outer circumferential surface 30 of the drive shaft 3, which is inserted in the through-hole 5 d.

The swash plate main portion 50 has, on the front surface 5 a, a first-side primary receiving portion 60 a and a second-side primary receiving portion 60 b. The first-side primary receiving portion 60 a and the second-side primary receiving portion 60 b are each formed to be flat. The first-side primary receiving portion 60 a and the second-side primary receiving portion 60 b are located between the weight 5 c and the first and second swash plate arms 5 e, 5 f. The first-side primary receiving portion 60 a and the second-side primary receiving portion 60 b are located on opposite sides of the bottom dead center plane D and have symmetrical shapes with respect to the bottom dead center plane D.

The weight 5 c is located on the front surface 5 a of the swash plate main portion 50 and is located between the drive shaft axis O and the bottom dead center associated part U. The weight 5 c has a substantially semi-circular cylindrical shape. As shown in FIG. 1, the weight 5 c extends from the front surface 5 a of the swash plate main portion 50 toward a movable body 13 a. The weight 5 c regulates the balance of weight of the swash plate 5.

As shown in FIG. 3, a first-side secondary receiving portion 61 a and a second-side secondary receiving portion 61 b are provided on the distal end of the weight 5 c. The first-side secondary receiving portion 61 a and the second-side secondary receiving portion 61 b are located on opposite sides of the bottom dead center plane D at positions in the vicinity of the distal end of the weight 5 c and have symmetrical shapes with respect to the bottom dead center plane D. Being located in the vicinity of the distal end of the weight 5 c, the first-side secondary receiving portion 61 a and the second-side secondary receiving portion 61 b are located closer to the bottom dead center associated part U than the first-side primary receiving portion 60 a and the second-side primary receiving portion 60 b in the first direction A1.

The weight 5 c has a first-side recess 62 a, which is continuous with the first-side secondary receiving portion 61 a, and a second-side recess 62 b, which is continuous with the second-side secondary receiving portion 61 b. As shown in FIG. 1, the first-side recess 62 a is recessed from the first-side secondary receiving portion 61 a toward the front surface 5 a. Although not illustrated, the second-side recess 62 b is also recessed from the second-side secondary receiving portion 61 b toward the front surface 5 a. As shown in FIG. 3, the first-side recess 62 a and the second-side recess 62 b are also located on opposite sides of the bottom dead center plane D and have symmetrical shapes with respect to the bottom dead center plane D.

The first and second swash plate arms 5 e, 5 f are located on the front surface 5 a of the swash plate main portion 50 and between the axis O of the drive shaft 3 and the top dead center associated part T. The first swash plate arm 5 e and the second swash plate arm 5 f are arranged on opposite sides of the bottom dead center plane D. As shown in FIG. 1, the first and second swash plate arms 5 e, 5 f extend from the front surface 5 a of the swash plate main portion 50 toward the lug plate 51.

As shown in FIG. 4, the lug plate 51 has a substantially annular shape with a through-hole 510. The drive shaft 3 is press fitted into the through-hole 510 of the lug plate 51. This allows the lug plate 51 to rotate integrally with the drive shaft 3. As shown in FIG. 1, a thrust bearing 55 is located between the lug plate 51 and the front wall 17 a.

As shown in FIG. 5, the lug plate 51 has a cylinder chamber 51 a. The cylinder chamber 51 a is located on the same axis as the axis O of the drive shaft 3. The chamber 51 a has a cylindrical shape that extends forward from the rear end of the lug plate 51. The rear end of the cylinder chamber 51 a communicates with the swash plate chamber 25.

As shown in FIG. 4, the first lug arm 53 a and the second lug arm 53 b are provided on the lug plate 51 at positions on opposite sides of the bottom dead center plane D. The first and second lug arms 53 a, 53 b are closer to the top dead center associated part T on the swash plate main portion 50 than the axis O of the drive shaft 3 and extend from the lug plate 51 toward the swash plate 5.

The lug plate 51 has first and second guide surfaces 57 a, 57 b between the first and second lug arms 53 a, 53 b. The first guide surface 57 a and the second guide surface 57 b are also located on opposite sides of the bottom dead center plane D. As shown in FIG. 1, the second guide surface 57 b is inclined such that the distance from the swash plate 5 gradually decreases from the outer circumference of the lug plate 51 toward the cylinder chamber 51 a. The same applies to the first guide surface 57 a.

The first and second swash plate arms 5 e, 5 f are inserted between the first and second lug arms 53 a, 53 b to mount the swash plate 5 to the drive shaft 3. The lug plate 51 and the swash plate 5 are thus coupled to each other with the first and second swash plate arms 5 e, 5 f located between the first and second lug arms 53 a, 53 b. When rotation of the lug plate 51 is transmitted from the first and second lug arms 53 a, 53 b to the first and second swash plate arms 5 e, 5 f, the swash plate 5 rotates with the lug plate 51 in the swash plate chamber 25.

With the first and second swash plate arms 5 e, 5 f located between the first and second lug arms 53 a, 53 b, the distal end of the first swash plate arm 5 e contacts the first guide surface 57 a, and the distal end of the second swash plate arm 5 f contacts the second guide surface 57 b. The first and second swash plate arms 5 e, 5 f slide on the first and second guide surfaces 57 a, 57 b, respectively. Accordingly, the inclination angle of the swash plate 5 is allowed to change from the maximum inclination angle shown in FIGS. 1 and 8 to the minimum inclination angle shown in FIG. 12, while substantially maintaining the position of the top dead center associated part T.

A first inclination range and a second inclination range are defined between the maximum inclination angle and the minimum inclination angle. The first inclination range is a range from an inclination angle close to the maximum inclination angle to the maximum inclination angle and includes the maximum inclination angle. On the other hand, the second inclination range is a range from the maximum inclination angle to the first inclination range and includes the minimum inclination angle. Specifically, the inclination angle of the swash plate 5 shown in FIGS. 8 and 9 is in the first inclination range, and the inclination angle of the swash plate 5 shown in FIGS. 11 and 12 is in the second inclination range. The inclination angle of the swash plate 5 shown in FIG. 10 is at the boundary between the first inclination range and the second inclination range.

As shown in FIG. 5, the actuator 13 includes the lug plate 51, the movable body 13 a, and a control pressure chamber 13 b.

As shown in FIG. 6, the movable body 13 a is fitted about the drive shaft 3. The movable body 13 a is thus located between the lug plate 51 and the swash plate 5 to move along the drive shaft axis O while sliding on the drive shaft 3. The movable body 13 a has a substantially cylindrical shape coaxial with the drive shaft 3. Specifically, as shown in FIG. 7, the movable body 13 a includes a movable body main portion 130, a first-side primary acting portion 70 a, a second-side primary acting portion 70 b, a first-side secondary acting portion 71 a, a second-side secondary acting portion 71 b, and a rotation stopper 134.

As shown in FIG. 6, the movable body main portion 130 includes a first cylindrical portion 131, a second cylindrical portion 132, and a coupling portion 133. The first cylindrical portion 131 is located at a position in the vicinity of the swash plate 5 in the movable body 13 a and extends along the axis O of the drive shaft 3. The first cylindrical portion 131 has the smallest diameter in the movable body main portion 130. The first cylindrical portion 131 has a rear end face 131 a, the diameter of which gradually decreases toward the rear end. As shown in FIG. 5, a ring groove 131 b is provided in the inner circumferential surface of the first cylindrical portion 131. An O-ring 49 c is fitted in the ring groove 131 b.

The second cylindrical portion 132 is located at a position on the movable body main portion 130 that is in the vicinity of the lug plate 51, that is, at the front end of the movable body 13 a. The outer diameter of the second cylindrical portion 132 is greater than that of the first cylindrical portion 131 and is greatest in the movable body main portion 130. The second cylindrical portion 132 has a flat front end face 132 a and a flat rear end face 132 b. With the drive shaft 3 inserted in the movable body 13 a, the front end face 132 a and the rear end face 132 b of the movable body 13 a are perpendicular to the axis O of the drive shaft 3. The second cylindrical portion 132 has a ring groove 132 c in the outer circumferential surface. An O-ring 49 d is fitted in the ring groove 132 c.

The coupling portion 133 is formed to have a diameter that is gradually increased from the first cylindrical portion 131 toward the second cylindrical portion 132. The coupling portion 133 couples the first cylindrical portion 131 to the rear end face 132 b of the second cylindrical portion 132.

As shown in FIG. 7, the first-side primary acting portion 70 a and the second-side primary acting portion 70 b are located on opposite sides of the bottom dead center plane D and at the rear end of a first cylindrical portion 131. The first-side primary acting portion 70 a and the second-side primary acting portion 70 b have symmetrical shapes with respect to the bottom dead center plane D. The first-side primary acting portion 70 a extends from the rear end of the first cylindrical portion 131 and toward the radially outer edge of the movable body 13 a. As shown in FIG. 6, the first-side primary acting portion 70 a extends further rearward than the rear end face 131 a of the first cylindrical portion 131. As shown in FIG. 7, the rear end face of the first-side primary acting portion 70 a is shaped as a cylinder with a generatrix extending in a direction perpendicular to the bottom dead center plane D.

The first-side secondary acting portion 71 a and the second-side secondary acting portion 71 b are formed on opposite sides of the bottom dead center plane D to extend over the rear end face 132 b of the second cylindrical portion 132 and the coupling portion 133. The first-side secondary acting portion 71 a and the second-side secondary acting portion 71 b have symmetrical shapes with respect to the bottom dead center plane D. As shown in FIG. 6, the first-side secondary acting portion 71 a protrudes rearward from the rear end face 132 b of the second cylindrical portion 132 and the coupling portion 133. As shown in FIG. 7, the first-side secondary acting portion 71 a extends further radially outward than the first-side primary acting portion 70 a and the second-side primary acting portion 70 b. The rear end face of the second-side secondary acting portion 71 a is shaped as a cylinder with a generatrix extending in a direction perpendicular to the bottom dead center plane D.

The first-side primary acting portion 70 a and the second-side primary acting portion 70 b are closer to the top dead center associated part T of the swash plate main portion 50 than the axis O of the drive shaft 3. On the other hand, the first-side secondary acting portion 71 a and the second-side secondary acting portion 71 b are closer to the bottom dead center associated part U of the swash plate main portion 50 than the axis O of the drive shaft 3. Accordingly, the first-side secondary acting portion 71 a and the second-side secondary acting portion 71 b are closer to the bottom dead center associated part U than the first-side primary acting portion 70 a and the second-side primary acting portion 70 b in the first direction A1.

The movable body 13 a is located between the lug plate 51 and the swash plate 5 and moves along the axis O of the drive shaft 3. This causes the first-side primary acting portion 70 a and the second-side primary acting portion 70 b to contact the first-side primary receiving portion 60 a and the second-side primary receiving portion 60 b shown in FIG. 3, respectively. Also, the first-side secondary acting portion 71 a and the second-side secondary acting portion 71 b shown in FIG. 7 are brought into contact with the first-side secondary receiving portion 61 a and the second-side secondary receiving portion 61 b, respectively. These contacting actions will be described below.

As shown in FIG. 6, the rotation stopper 134 is formed at the rear end of the first cylindrical portion 131. The rotation stopper 134 has a rectangular shape as shown in FIG. 7 and extends vertically from the first cylindrical portion 131 toward the top dead center associated part T of the swash plate main portion 50. The rotation stopper 134 is located between the first swash plate arm 5 e and the second swash plate arm 5 f, which are shown in FIG. 3. As the swash plate 5 rotates, the rotation stopper 134 contacts the first swash plate arm 5 e or the second swash plate arm 5 f. That is, the rotation stopper 134 restricts pivoting motion of the movable body 13 a about the axis O. This allows the movable body 13 a to be rotated integrally with the lug plate 51 and the swash plate 5 by rotation of the drive shaft 3.

As shown in FIG. 5, the control pressure chamber 13 b is defined by the second cylindrical portion 132, the coupling portion 133, the cylinder chamber 51 a, and the drive shaft 3. The control pressure chamber 13 b and the swash plate chamber 25 are sealed off from each other by the O-rings 49 c, 49 d.

The drive shaft 3 has an axial passage 3 a and a radial passage 3 b. The axial passage 3 a extends from the rear end of the drive shaft 3 toward the front end along the drive shaft axis O. The radial passage 3 b extends in a radial direction from the front end of the axial passage 3 a and opens in the outer circumferential surface 30 of the drive shaft 3. As shown in FIG. 1, the rear end of the axial passage 3 a communicates with the pressure regulation chamber 31. The radial passage 3 b communicates with control pressure chamber 13 b as shown in FIG. 5. The axial passage 3 a and the radial passage 3 b connect the pressure regulation chamber 31 to the control pressure chamber 13 b.

As shown in FIG. 1, the drive shaft 3 has a threaded portion 3 c at the front end. The drive shaft 3 is connected to a pulley (not shown) via the threaded portion 3 c.

The pistons 9 are single-headed pistons each having a head 90 only at the rear end. Each piston 9 is accommodated in the corresponding one of the cylinder bores 21 a and is allowed to reciprocate in the cylinder bore 21 a. The head 90 of each piston 9 and the valve assembly plate 23 define a compression chamber 57 in the corresponding cylinder bore 21 a.

Each piston 9 has an engaging portion 9 a. Each engaging portion 9 a accommodates a pair of hemispherical shoes 11 a, 11 b. The shoes 11 a, 11 b correspond to a conversion mechanism of the present invention. Each shoe 11 a slides on the front surface 5 a of the swash plate main portion 50. In contrast, each shoe 11 b slides on the rear surface 5 b of the swash plate main portion 50. In this manner, the swash plate main portion 50 causes the shoes 11 a, 11 b to move along the front surface 5 a and the rear surface 5 b. Accordingly, the shoes 11 a, 11 b convert rotation of the swash plate 5 into reciprocation of the pistons 9, and the pistons 9 reciprocate in the cylinder bores 21 a by a stroke corresponding to the inclination angle of the swash plate 5. Instead of providing the shoes 11 a, 11 b, a wobble plate type conversion mechanism may be employed, in which a wobble plate is provided on the rear surface 5 b of the swash plate main portion 50 via a thrust bearing, and the wobble plate and the pistons 9 are connected to each other with connecting rods.

As shown in FIG. 2, the control mechanism 15 includes a low-pressure passage 15 a, a high-pressure passage 15 b, a control valve 15 c, an orifice 15 d, the axial passage 3 a, and the radial passage 3 b.

The low-pressure passage 15 a is connected to the pressure regulation chamber 31 and the suction chamber 33. The low-pressure passage 15 a, the axial passage 3 a, and the radial passage 3 b connect the control pressure chamber 13 b, the pressure regulation chamber 31, and the suction chamber 33 to one another. The high-pressure passage 15 b is connected to the pressure regulation chamber 31 and the discharge chamber 35. The high-pressure passage 15 b, the axial passage 3 a, and the radial passage 3 b connect the control pressure chamber 13 b, the pressure regulation chamber 31, and the discharge chamber 35 to one another.

The control valve 15 c is arranged in the low-pressure passage 15 a. The low-pressure control valve 15 c is configured to adjust the opening degree of the low-pressure passage 15 a based on the pressure in the suction chamber 33. The high-pressure passage 15 b also has the orifice 15 d.

The inlet 250 shown in FIG. 1 is connected to the pipe 203, which is connected to the evaporator 103, and the outlet 360 is connected to the pipe 201, which is connected to the condenser 101. The condenser 101 is connected to the evaporator 103 through a pipe 202 and an expansion valve 102. The refrigeration circuit in the vehicle air conditioner is configured as described above.

When the drive shaft 3 rotates to rotate the swash plate 5, the pistons 9 are reciprocated in the cylinder bores 21 a. Accordingly, the volume of each compression chamber 57 changes in accordance with the stroke of the pistons 9. Thus, refrigerant gas is drawn into the swash plate chamber 25 from the evaporator 103 via the inlet 250 and then into the compression chambers 57 from the suction passage 39 via the suction chamber 33. The refrigerant gas is then compressed in each compression chamber 57. The refrigerant that is compressed in the compression chambers 57 is discharged to the discharge chamber 35 and is delivered to the condenser 101 through the outlet 360.

The actuator 13 changes the inclination angle of the swash plate 5 to increase or decrease the stroke of the pistons 9, thereby varying the displacement.

When changing the inclination angle of the swash plate 5 from the minimum inclination angle shown in FIG. 12 to the maximum inclination angle shown in FIG. 8, that is, when increasing the stroke of the pistons 9 to increase the displacement, the control valve 15 c of the control mechanism 15 shown in FIG. 2 increases the opening degree of the low-pressure passage 15 a. This substantially equalizes the pressure in the pressure regulation chamber 31 and thus the pressure in the control pressure chamber 13 b with the pressure in the suction chamber 33. Thus, compression reaction force that acts on the swash plate 5 from the pistons 9 causes the movable body 13 a to move along the axis O of the drive shaft 3 toward the lug plate 51 as shown in FIG. 9.

The compression reaction force acting on the swash plate 5 and the urging force of the restoration spring 37 cause the first and second swash plate arms 5 e, 5 f to slide on the first and second guide surfaces 57 a, 57 b, respectively, to move away from the axis O of the drive shaft 3.

The swash plate 5 thus increases the inclination angle by pivoting to bring the bottom dead center associated part U closer to the lug plate 51, while substantially maintaining the position of the top dead center associated part T. As a result, the stroke of the pistons 9 is increased, so that the displacement of the compressor per rotation of the drive shaft 3 is increased. When the inclination angle of the swash plate 5 is maximized as shown in FIG. 8, the displacement of the compressor per rotation of the drive shaft 3 is maximized. In this state, the movable body 13 a is at the deepest position in the cylinder chamber 51 a.

When the displacement is large as described above, the pressure in the discharge chamber 35 is high, and the differential pressure of the discharge chamber 35 relative to the condenser 101 becomes greater than or equal to the predetermined value. In this case, since the check valve 38 shown in FIG. 1 is switched to the open state, the refrigerant gas in the discharge chamber 35 flows into the condenser 101.

To reduce the displacement, the control valve 15 c of the control mechanism 15 shown in FIG. 2 reduces the opening degree of the low-pressure passage 15 a. This increases the pressure in the pressure regulation chamber 31, so that the pressure in the control pressure chamber 13 b is increased. Hereinafter, an example will be described with reference to FIGS. 8 to 12, in which the inclination angle of the swash plate 5 is changed from the maximum inclination angle to the minimum inclination angle.

When the inclination angle of the swash plate 5 is within the first inclination range, which includes the maximum inclination angle as shown in FIGS. 8 and 9, the first-side primary acting portion 70 a contacts the first-side primary receiving portion 60 a. Likewise, the second-side primary acting portion 70 b shown in FIG. 7 contacts the second-side primary receiving portion 60 b shown in FIG. 3. On the other hand, when the inclination angle of the swash plate 5 is in the first inclination range as shown in FIGS. 8 and 9, the first-side secondary acting portion 71 a is located in the first-side recess 62 a of the weight 5 c and is distant from the first-side secondary receiving portion 61 a. The first-side secondary acting portion 71 a does not contact the first-side secondary receiving portion 61 a. Likewise, the second-side secondary acting portion 71 b shown in FIG. 7 is located in the second-side recess 62 b shown in FIG. 3 and is distant from the second-side secondary receiving portion 61 b shown in FIG. 3. The second-side secondary acting portion 71 b does not contact the second-side secondary receiving portion 61 b. Hereinafter, the state will be referred to as a first contact state.

When the pressure in the control pressure chamber 13 b is increased, the movable body 13 a, which is at the deepest position in the cylinder chamber 51 a as shown in FIG. 8, is moved toward the swash plate 5 along the axis O in the cylinder chamber 51 a as shown in FIG. 9. This causes the first-side primary acting portion 70 a and the second-side primary acting portion 70 b to push the first-side primary receiving portion 60 a and the second-side primary receiving portion 60 b rearward along the axis O, respectively. That is, the movable body 13 a pushes the swash plate 5 in the swash plate chamber 25 rearward along the axis O via the first-side primary acting portion 70 a and the second-side primary acting portion 70 b.

The swash plate 5 thus decreases the inclination angle by pivoting to moving the bottom dead center associated part U away from the lug plate 51, while substantially maintaining the position of the top dead center associated part T as shown in FIG. 9. As a result, the stroke of the pistons 9 is decreased, so that the displacement of the compressor per rotation of the drive shaft 3 is decreased.

When the pressure in the control pressure chamber 13 b is further increased, and the movable body 13 a further pushes the swash plate 5 via the first-side primary acting portion 70 a and the second-side primary acting portion 70 b, the swash plate 5 is displaced to the inclination angle that corresponds to the boundary between the first inclination range and the second inclination range as shown in FIG. 10. In other words, the inclination angle of the swash plate 5 is reduced to the inclination angle that corresponds to the boundary between the first inclination range and the second inclination range, so that the displacement of the compressor is further reduced.

When the inclination angle of the swash plate 5 reaches the boundary between the first inclination range and the second inclination range, the first-side primary acting portion 70 a contacts the first-side primary receiving portion 60 a, and the first-side secondary acting portion 71 a contacts the first-side secondary receiving portion 61 a. Likewise, the second-side primary acting portion 70 b shown in FIG. 7 contacts the second-side primary receiving portion 60 b shown in FIG. 3, and the second-side secondary acting portion 71 b contacts the second-side secondary receiving portion 61 b.

Also, when the inclination angle of the swash plate 5 is reduced to the inclination angle that corresponds to the boundary between the first inclination range and the second inclination range, so that the displacement of the compressor is reduced, the pressure in the discharge chamber 35 is lowered, and the differential pressure of the discharge chamber 35 relative to the condenser 101 falls below the predetermined value. This switches the check valve 38 shown in FIG. 1 from the open state to the closed state to prevent the refrigerant gas in the discharge chamber 35 from flowing back to the condenser 101.

When the pressure in the control pressure chamber 13 b is further increased, the movable body 13 a is moved further toward the swash plate 5 along the axis O in the cylinder chamber 51 a as shown in FIG. 11, so that the inclination angle of the swash plate 5 reaches the second inclination range.

When the inclination angle of the swash plate 5 is within the second inclination range, which includes the minimum inclination angle as shown in FIGS. 11 and 12, the first-side secondary acting portion 71 a contacts the first-side secondary receiving portion 61 a. Likewise, the second-side secondary acting portion 71 b shown in FIG. 7 contacts the second-side secondary receiving portion 61 b shown in FIG. 3. On the other hand, when the inclination angle of the swash plate 5 is in the second inclination range as shown in FIGS. 11 and 12, the first-side primary acting portion 70 a is distant from the first-side primary receiving portion 60 a. The first-side primary acting portion 70 a thus does not contact the first-side primary receiving portion 60 a. Likewise, the second-side primary acting portion 70 b shown in FIG. 7 is distant from the second-side primary receiving portion 60 b shown in FIG. 3 and does not contact the second-side primary receiving portion 60 b. Hereinafter, the state will be referred to as a second contact state.

When the inclination angle of the swash plate 5 is within the second inclination range, the first-side secondary acting portion 71 a and the second-side secondary acting portion 71 a push the first-side secondary receiving portion 61 a and the second-side secondary receiving portion 61 a rearward along the axis O, respectively. This changes the inclination angle of the swash plate 5 to the minimum inclination angle as shown in FIG. 12. When the swash plate 5 is at the minimum inclination angle, the displacement of the compressor per rotation of the drive shaft 3 is minimized. In this state, the movable body 13 a is at the rearmost position in the cylinder chamber 51 a.

As described above, in the first inclination range, the first-side primary acting portion 70 a and the second-side primary acting portion 70 b of the movable body 13 a contact the first-side primary receiving portion 60 a and the second-side primary receiving portion 60 h of the swash plate main portion 50, respectively. Also, in the second inclination range, the first-side secondary acting portion 71 a and the second-side secondary acting portion 71 b contact the first-side secondary receiving portion 61 a and the second-side secondary receiving portion 61 b of the weight 5 c, respectively.

The first-side secondary acting portion 71 a and the second-side secondary acting portion 71 b are located between the bottom dead center associated part U and the first-side and second-side primary acting portions 70 a, 70 b in the first direction A1. The positions at which the first-side secondary acting portion 71 a and the second-side secondary acting portion 71 b respectively contact the first-side secondary receiving portion 61 a and the second-side secondary receiving portion 61 b are distant from the center of moment of the load acting on the swash plate 5 and distant from the top dead center associated part T, at which the compression reaction force is great. On the other hand, the positions at which the first-side primary acting portion 70 a and the second-side primary acting portion 70 b respectively contact the first-side primary receiving portion 60 a and the second-side primary receiving portion 60 b are closer to the center of moment of the load acting on the swash plate 5 and closer to the top dead center associated part T, at which the compression reaction force is great, than the positions at which the first-side secondary acting portion 71 a and the second-side secondary acting portion 71 b respectively contact the first-side secondary receiving portion 61 a and the second-side secondary receiving portion 61 b.

The first inclination range includes the maximum inclination angle and is close to the maximum inclination angle in the range of change of the inclination angle of the swash plate 5. The closer to the maximum inclination angle the swash plate 5 is, the greater the displacement becomes. Accordingly, it becomes easier to increase the pressure in the control pressure chamber 13 b, and as a result, it becomes easier to increase the thrust of the movable body 13 a. The second inclination range includes the minimum inclination angle and is close to the minimum inclination angle in the range of change of the inclination angle of the swash plate 5. The closer to the minimum inclination angle the swash plate 5 is, the smaller the displacement becomes. Accordingly, it becomes more difficult to increase the pressure in the control pressure chamber 13 b, and as a result, it becomes more difficult to increase the thrust of the movable body 13 a.

That is, in the first inclination range, in which it is easy to increase the thrust of the movable body 13 a, the first-side primary acting portion 70 a and the second-side primary acting portion 70 b respectively contact the first-side primary receiving portion 60 a and the second-side primary receiving portion 60 b at positions close to the center of moment of the load acting on the swash plate 5 and at positions close to the top dead center associated part T, at which the compression reaction force is great, so that the movable body 13 a pushes the swash plate 5. Thus, even if the load acting on the movable body 13 a is increased when the inclination angle is reduced, an increase in the thrust of the movable body 13 a allows the inclination angle to be quickly changed in response to changes in the driving state of the vehicle, so that a high controllability is achieved. In this case, the stroke of the movable body 13 a when changing the inclination angle is reduced. This allows the axial dimension of the actuator 13 to be reduced.

This operation will be described based on a comparison example. As shown in FIGS. 13 and 14, a compressor of the comparison example does not have the first-side primary acting portion 70 a or the second-side primary acting portion 70 b on the movable body 13 a. Also, the weight 5 c of the swash plate 5 does not have the first-side recess 62 a or the second-side recess 62 b. Accordingly, in the compressor of the comparison example, the first-side secondary acting portion 71 a and the second-side secondary acting portion 71 b always contact the weight 5 c regardless of the inclination angle of the swash plate 5.

In the compressor of the comparison example, when the inclination angle of the swash plate 5 is changed from the maximum inclination angle to the minimum inclination angle, the movable body 13 a always pushes the swash plate 5 via the first-side secondary acting portion 71 a and the second-side secondary acting portion 71 b. Thus, in the compressor of the comparison example, the positions at which the first-side secondary acting portion 71 a and the second-side secondary acting portion 71 b contact the weight 5 c are distant from the center of moment of the load acting on the swash plate 5, and the movable body 13 a is likely to be influenced by the compression reaction force. In contrast, when the inclination angle of the swash plate 5 is changed from the maximum inclination angle to the minimum inclination angle as shown in FIG. 14, the stroke of the movable body 13 a is a length S2. To ensure the stroke of the movable body 13 a, the swash plate arms 5 e, 5 f need to be extended along the axis O to widen the space between the lug plate 51 and the swash plate 5. Also, to ensure the stroke of the movable body 13 a, the cylinder chamber 51 a needs to be enlarged in the direction of the axis O together with the lug plate 51, which consequently increases the size of the actuator 13 in the direction of the axis O.

In the compressor of the comparison example, the first-side secondary acting portion 71 a and the second-side secondary acting portion 71 b respectively contact the first-side secondary receiving portion 61 a and the second-side secondary receiving portion 61 b, so that the movable body 13 a pushes the swash plate 5.

In the first cylindrical portion 131 of the movable body 13 a, the first-side primary acting portion 70 a and the second-side primary acting portion 70 b are located between the axis O of the drive shaft 3 and the top dead center associated part T. This sufficiently reduces the stroke of the movable body 13 a required for changing the inclination angle of the swash plate 5 in the first inclination range.

Thus, as shown in FIG. 12, the stroke of the movable body 13 a required for changing the inclination angle of the swash plate 5 from the maximum inclination angle to the minimum inclination angle is a length S1, which is shorter than the length S2 of the stroke in the comparison example shown in FIG. 14. Thus, the lug plate 51 and the swash plate 5 can be brought closer to each other along the axis O as shown in FIG. 12, so that the actuator 13 can be reduced in size in the direction of the axis O.

Also, in the second inclination range, in which it is difficult to increase the thrust of the movable body 13 a, the first-side secondary acting portion 71 a and the second-side secondary acting portion 71 b respectively contact the first-side secondary receiving portion 61 a and the second-side secondary receiving portion 61 b to push the swash plate 5 at positions distant from the center of moment of the load acting on the swash plate 5 and at positions distant from the top dead center associated part T, at which the compression reaction force is great.

In the movable body 13 a, the first-side secondary acting portion 71 a and the second-side secondary acting portion 71 b are located between the axis O and the bottom dead center associated part U of the swash plate main portion 50. Thus, when changing the inclination angle of the swash plate 5 within the second inclination range, the influence of the load such as the compression reaction force acting on the movable body 13 a is further effectively reduced.

Thus, even if the load acting on the movable body 13 a is decreased when the inclination angle is reduced, the inclination angle can be quickly changed in response to changes in the driving state of the vehicle without increasing the thrust of the movable body 13 a, so that a high controllability is achieved. In this case, the pressure receiving area of the movable body 13 a does not need to be increased. Thus, the size of the movable body 13 a and that of the actuator 13 can be reduced.

Particularly, when the inclination angle of the swash plate 5 is changed to the inclination angle that corresponds to the boundary between the first inclination range and the second inclination range, the contact state is switched between the first contact state and the second contact state. Thus, the first-side primary acting portion 70 a and the second-side primary acting portion 70 b, the first-side primary receiving portion 60 a and the second-side primary receiving portion 60 b, the first-side secondary acting portion 71 a and the second-side secondary acting portion 71 b, and the first-side secondary receiving portion 61 a and the second-side secondary receiving portion 61 b do not interfere with each other. Therefore, the above described operations can be effectively performed.

Accordingly, the compressor of the embodiment achieves high controllability while reducing the size.

The check valve 38 is switched between the open state and the closed state at the boundary between the second inclination range and the first inclination range. Thus, even if the drive shaft 3 is rotating, the check valve 38 in the closed state prevents the refrigerant gas from flowing back from the condenser 101 to the discharge chamber 35 as long as the inclination angle of the swash plate 5 is in the second inclination range, which includes the minimum inclination angle, and the check valve 38 is switched to the OFF state. On the other hand, the check valve 38 in the open state allows refrigerant gas to flow from the discharge chamber 35 to the condenser 101 as long as the inclination angle of the swash plate 5 is in the first inclination range, which includes the maximum inclination angle, and the check valve 38 is switched to the ON state. In this manner, a clutchless compressor is obtained, in which the drive shaft 3 is not disconnected from the power source by an electromagnetic clutch.

The movable body 13 a has the first-side primary acting portion 70 a, the second-side primary acting portion 70 b, the first-side secondary acting portion 71 a, and the second-side secondary acting portion 71 b, but has no other acting portions. The movable body 13 a is thus easy to manufacture.

The first-side primary acting portion 70 a and the second-side primary acting portion 70 b are located on opposite sides of the bottom dead center plane D to form a pair, and the first-side secondary acting portion 71 a and the second-side secondary acting portion 71 b are located on opposite sides of the bottom dead center plane D to form a pair. In accordance with these, the first-side primary receiving portion 60 a and the second-side primary receiving portion 60 b are located on opposite sides of the bottom dead center plane D to form pair, and the first-side secondary receiving portion 61 a and the second-side secondary receiving portion 61 b are located on opposite sides of the bottom dead center plane D to form a pair.

With this configuration, the swash plate 5 is unlikely to be inclined in direction other than inclination angle changing directions eve if the movable body 13 a is pushed in the above described manners. This allows the movable body 13 a to properly change the inclination angle of the swash plate 5.

Since the swash plate main portion 50 of the swash plate 5 has the weight 5 c, the balance of weight of the swash plate 5 is properly adjusted during rotation, allowing the swash plate 5 to rotate properly. Since the weight 5 c has the first-side secondary receiving portion 61 a and the second-side secondary receiving portion 61 b, the first-side secondary acting portion 71 a and the second-side secondary acting portion 71 b are allowed to properly contact the first-side secondary receiving portion 61 a and the second-side secondary receiving portion 61 b, while simplifying the shape of the swash plate 5.

Although the invention has been described with reference to the embodiment, the invention is not limited to the embodiment but may be modified within the scope of the invention.

For example, in the range in change the inclination angle of the swash plate 5 from the maximum inclination angle to the minimum inclination angle, a range may be defined in which the first-side primary acting portion 70 a and the second-side primary acting portion 70 b respectively push the first-side primary receiving portion 60 a and the second-side primary receiving portion 60 b, and the first-side secondary acting portion 71 a and the second-side secondary acting portion 71 b respectively push the first-side secondary receiving portion 61 a and the second-side secondary receiving portion 61 b.

Also, the first cylindrical portion 131 may be formed without the first-side primary acting portion 70 a or the second-side primary acting portion 70 b. Instead, the first-side primary receiving portion 60 a and the second-side primary receiving portion 60 b may have projecting shapes that are contactable with the rear end face 131 a of the first cylindrical portion 131. That is, the rear end face 131 a of the first cylindrical portion 131 may function as a primary acting portion. The movable body 13 a may be formed without the first-side secondary acting portion 71 a or the second-side secondary acting portion 71 b. Instead may have an annular secondary acting portion that is contactable with the first-side secondary receiving portion 61 a and the second-side secondary receiving portion 61 b. These configurations achieve the same advantages as the compressor of the above illustrated embodiment. With this configuration, the movable body 13 a does not need to have the rotation stopper 134, which simplifies the manufacture of the movable body 13 a.

Further, in addition to the first-side primary acting portion 70 a, the second-side primary acting portion 70 b, the first-side secondary acting portion 71 a, and the second-side secondary acting portion 71 b, the movable body 13 a may have an additional acting portion, and the swash plate 5 may have receiving portions that corresponds to the above acting portions.

The movable body 13 a may have only one of the first-side primary acting portion 70 a and the second-side primary acting portion 70 b and one of the first-side secondary acting portion 71 a and the second-side secondary acting portion 71 b. In this case, the swash plate 5 is only required to have one of the first-side primary receiving portion 60 a and the second-side primary receiving portion 60 b and one of the first-side secondary receiving portion 61 a and the second-side secondary receiving portion 61 b. This facilitates the manufacture of the movable body 13 a and the swash plate 5.

Further, the control valve 15 c may be provided in the high-pressure passage 15 b of the control mechanism 15, and the orifice 15 d may be provided in the low-pressure passage 15 a. In this case, the control valve 15 c is allowed to adjust the flow rate of high-pressure refrigerant flowing through the high-pressure passage 15 b. This allows the high-pressure in the discharge chamber 35 to promptly increase the pressure in the control pressure chamber 13 b and to promptly reduce the displacement. Also, the control valve 15 c may be replaced by a three-way valve connected to the low-pressure passage 15 a and the high-pressure passage 15 b. In this case, the opening degree of the three-way valve is adjusted to regulate the flow rate of refrigerant flowing through the low-pressure passage 15 a and the high-pressure passage 15 b. 

1. A variable displacement swash-plate compressor comprising: a housing, in which a swash plate chamber and a cylinder bore are defined; a drive shaft rotationally supported by the housing; a swash plate rotational in the swash plate chamber by rotation of the drive shaft; a link mechanism arranged between the drive shaft and the swash plate, wherein the link mechanism allows change of an inclination angle of the swash plate with respect to a direction perpendicular to an axis of the drive shaft; a piston reciprocally received in the cylinder bore; a conversion mechanism, which causes the piston to reciprocate in the cylinder bore by a stroke corresponding to the inclination angle of the swash plate through rotation of the swash plate; an actuator configured to change the inclination angle of the swash plate; and a control mechanism, which controls the actuator, wherein the link mechanism includes a lug member, which is located in the swash plate chamber and is fixed to the drive shaft, and a transmitting member, which transmits rotation of the lug member to the swash plate, the actuator includes the lug member, a movable body, which is rotational integrally with the swash plate, wherein the movable body is configured to change the inclination angle of the swash plate by moving along the axis of the drive shaft, and a control pressure chamber, which is defined by the lug member and the movable body, wherein the movable body is moved by changing a pressure in the control pressure chamber, the movable body has a primary acting portion and a secondary acting portion, which are configured to push the swash plate with the pressure in the control pressure chamber, the swash plate has a primary receiving portion and a secondary receiving portion, which are pushed by the primary acting portion and the secondary acting portion, a top dead center associated part for positioning the piston at a top dead center and a bottom dead center associated part for positioning the piston at the bottom dead center are defined on the swash plate, the primary acting portion is configured to contact the primary receiving portion to push the swash plate when the inclination angle of the swash plate is maximized, the secondary acting portion is configured to contact the secondary receiving portion to push the swash plate when the inclination angle of the swash plate is minimized, and the secondary acting portion is located between the primary acting portion and the bottom dead center associated part.
 2. The variable displacement swash-plate compressor according to claim 1, wherein an inclination range in which the inclination angle of the swash plate changes includes a first inclination range, which includes the maximum inclination angle, and a second inclination range, which includes the minimum inclination angle, in the first inclination range, the primary acting portion contacts the primary receiving portion, and the secondary acting portion is separated from the secondary receiving portion, and in the second inclination range, the primary acting portion is separated from the primary receiving portion, and the secondary acting portion contacts the secondary receiving portion.
 3. The variable displacement swash-plate compressor according to claim 2, wherein the primary acting portion is located between the axis of the drive shaft and the top dead center associated part.
 4. The variable displacement swash-plate compressor according to claim 2, wherein the secondary acting portion is located between the axis of the drive shaft and the bottom dead center associated part.
 5. The variable displacement swash-plate compressor according to claim 2, wherein a discharge chamber is defined in the housing, a check valve is located between the discharge chamber and an external condenser, when a differential pressure of the discharge chamber relative to the condenser is greater than or equal to a predetermined value, the check valve is switched to an open state, when the differential pressure of the discharge chamber relative to the condenser is less than the predetermined value, the check valve is switched to a closed state to prevent refrigerant gas from flowing back from the condenser to the discharge chamber, and a boundary between the second inclination range and the first inclination range is defined in accordance with time at which the check valve is switched from the closed state to the open state as the inclination angle of the swash plate is increased from the minimum inclination angle.
 6. The variable displacement swash-plate compressor according to claim 1, wherein the primary acting portion is one of a first-side primary acting portion and a second-side primary acting portion, which form a pair, wherein the first-side primary acting portion and the second-side primary acting portion are arranged on opposite sides of a bottom dead center plane, which includes the bottom dead center associated part and the axis of the drive shaft, the primary receiving portion is one of a first-side primary receiving portion, which corresponds to the first-side primary acting portion, and a second-side primary receiving portion, which corresponds to the second-side primary acting portion, the secondary acting portion is one of a first-side secondary acting portion and a second-side secondary acting portion, which form a pair, wherein the first-side secondary acting portion and the second-side secondary acting portion are arranged on opposite sides of the bottom dead center plane, and the secondary receiving portion is one of a first-side secondary receiving portion, which corresponds to the first-side secondary acting portion, and a second-side secondary receiving portion, which corresponds to the second-side secondary acting portion.
 7. The variable displacement swash-plate compressor according to claim 1, wherein the swash plate has a weight, which is located between the axis of the drive shaft and the bottom dead center associated part and projects toward the movable body, and the secondary receiving portion is located on the weight. 